Augmented reality (AR) is a live direct or indirect view of a physical, real-world environment where elements of the environment are “augmented” by computer-generated perceptual information across one or more sensory modalities, such as visual, auditory, haptic, somatosensory, and/or olfactory. Whereas virtual reality replaces a real world environment with a simulated environment, augmented reality alters one's current perception of a real world environment.